1. Field of the Invention
The present invention relates to a particle carrying device for carrying particles used in an electrophotographic device or the like toward a predetermined direction, and more particularly to a particle carrying device which can be detachably installed onto a particle collection unit without dropping particles.
2. Description of Related Art
Conventionally, an electrophotographic device include a particle carrying device for collecting and carrying toner particles used in the electrophotographic device toward a wasted toner particle container. As the particle carrying device mentioned above, for example, a particle carrying device is disclosed in Japanese Patent Publication No. 63-10424.
First, the structure of the particle carrying device will be explained with reference to FIGS. 2-5. FIG. 2 is a schematic structure view of a general electrophotographic device 50. The electrophotographic device 50 comprises a photosensitive drum 52, around which a charging device 54, an exposing device 56, a developing device 58, a transferring device 60 and a cleaner 62 are provided.
The photosensitive drum 52 comprises a conductive drum body which is grounded and a photoconductivity layer which is provided on the conductive drum body. The photosensitive drum 52 rotates in the direction indicated by an arrow A as shown in FIG. 2. The charging device 54, the exposing device 56, the developing device 58, the transferring device 60 and the cleaner 62 are in order arranged according to the rotational direction of the photosensitive drum 52.
The charging device 54 is a well-known corotron. The exposing device 56 comprises a laser beam emitter and a polygonal mirror which are known well.
The developing device 58 comprises a hopper 64A, a rotational body 64B, a wasted toner particle container 64C and a brush roller blade 64D. The hopper 64A stores unused toner particles therein. The toner particles are made of a one-component developer comprising magnetic toner particles or are made of a two-component developer comprising toner particles and magnetic carriers. Moreover, the hopper 64A has an opening on the lower portion thereof. The rotational body 64B rotates in the direction of arrow B, as shown in FIG. 2. A part of the rotational body 64B sticks out of the hopper 64A through the opening. The rotational body 64B comprises a sleeve which is a nonmagnetic body and a magnetic roller which is disposed rotatably inside of the sleeve. The sleeve and the magnetic roller can rotate relatively each other. Moreover, the rotational body 64B is disposed opposite to the photosensitive drum 52 and spaced therefrom at a predetermined interval. The wasted toner particle container 64C stores wasted toner particles which are discharged from the cleaner 62 (to be described later). The brush roller blade 64D is fixed to the outside wall of the hopper 64A. One end of the brush roller blade 64D is positioned close to the surface of the rotational body 64B. The amount of toner particles on the rotational body 64B are controlled with the brush roller blade 64D. The developing device 58 having the above-mentioned structure is detachably installed in the main body of the electrophotographic device 50 as a single unit.
The transferring device 60 is a well-known corotron.
The cleaner 62 is used for removing the toner particles remaining on the photosensitive drum 52. The cleaner 62 comprises a case 62A and a cleaning blade 62B. A screw 70 for carrying the wasted toner particles is provided in the case 62A. The cleaning blade 62B is made of urethane rubber, and comes in contact with the surface of the photosensitive drum 52. If less than all toner particles are transferred onto a paper by the transferring device 60, the untransferred toner particles remain on the surface of the photosensitive drum 52. The remaining toner particles are removed from the surface of the photosensitive drum 52 by the cleaning blade 62B. Alternatively, a fur brush may be used instead of the urethane rubber cleaning blade 62B.
Next, the operation of the electrophotographic device 50 will be explained.
In the electrophotographic device 50, the charging device 54 evenly distributes a charge having a predetermined polarity onto the surface of the photosensitive drum 52. Next, the exposing device 56 irradiates the photosensitive drum 52 with the laser beam based on an image data. Accordingly, an electrostatic latent image of the image is formed on the surface of the photosensitive drum 52. The electrostatic latent image is developed to a visible image with the toner particles by the developing device 58, so that a toner particle image is formed on the surface of the photosensitive drum 52. Further, the toner particle image is transferred onto a paper 66 by the transferring device 60. At this time, if less than all toner particles are transferred onto the paper 66 by the transferring device 60, some toner particles remain on the surface of the photosensitive drum 52. However, the remaining toner particles are collected from the surface of the photosensitive drum 52 by the cleaner 62. After the remaining toner particles are removed from the surface of the photosensitive drum 52, the photosensitive drum 52 is charged again with the predetermined polarity by the charging device 54. After this, the above-mentioned process is repeated.
In the electrophotographic device 50 having the above-mentioned structure, the wasted toner particle carrying device comprises the cleaner 62 and a carrying pipe 68. The cleaner 62 and the wasted toner particle container 64C are connected each other through the carrying pipe 68. As shown in FIG. 5, the head portion 77 of the carrying pipe 68 is detachable from the wasted toner particle container 64C. The wasted toner particles collected by the cleaner 62 are carried into the carrying pipe 68 by the screw 70 disposed in the cleaner 62, and are stored in the wasted toner particle container 64C.
Next, the structure and the operation of the connecting portion between the head portion 77 of the carrying pipe 68 and the wasted toner particle container 64C will be explained in detail with reference to FIGS. 3-5.
As described above, the developing device 58 is detachably installed in the main body. Therefore, the head portion 77 of the carrying pipe 68 is detachable from the wasted toner particle container 64C. When the head portion 77 of the carrying pipe 68 is detached from the wasted toner particle container 64C, the wasted toner particles may drop out of the openings of the carrying pipe 68 and the wasted toner particle container 64C. Therefore, there is a need to provide means for preventing the toner particles from dropping out of either opening. FIG. 4A is a cross-sectional view of the head portion of the carrying pipe 68 from the cleaner 62. FIG. 4B is a partial cross-sectional view of the wasted toner particle container 64C. FIG. 5 is a view showing the connecting portion between the head portion 77 of the carrying pipe 68 and the wasted toner particle container 64C.
As shown in FIG. 4B, when the head portion 77 of the carrying pipe 68 is not connected to the wasted toner particle container 64C, an opening 72 of the wasted toner particle container 64C is covered with a lid 74. Since the lid 74 is supported pivotably centering on a shaft 76, the lid 74 can open and shut the opening 72. The head portion 77 of the carrying pipe 68 is formed so as to be pointed (i.e., having an abbreviated tapered shape). The pointed head of the carrying pipe 68 has an opening 77A. And, in the head portion 77, a valve 78 is resiliently urged by a spring 80 at all times to shut the opening 77A. When the head portion 77 of the carrying pipe 68 is connected to the wasted toner particle container 64C, a stick member (not shown) pivots the lid 74 so as to open the opening 72. And, as the head portion 77 of the carrying pipe 68 is inserted into the opening 72, a pin 82 disposed in the wasted toner particle container 64C pushes the valve 78 against the spring 80. Accordingly, the opening 77A of the pointed head of the carrying pipe 68 is opened. Thus, the carrying pipe 68 is installed completely into the opening 72 of the wasted toner particle container 64C.
However, in the above-mentioned wasted toner particle carrying device, there are the following problems. Since the toner particles collected by the cleaner 62 are carried to the wasted toner particle container 64C through the carrying pipe 68, the wasted toner particles are present in the head portion 77 of the carrying pipe 68 at all times. Further, when the carrying pipe 68 is removed from the wasted toner particle container 64C, the valve 78 returns to the former state by expansion of the spring 80. Then, according to the operation of the spring 80, the wasted toner particles which are present in the head portion 77 are pushed out of the opening 77A of the carrying pipe 68 by the valve 78. Therefore, the surroundings of the connection portion between the head portion 77 of the carrying pipe 68 and the wasted toner particle container 64C are stained with the toner particles.